1. Field of the Invention
Example embodiments of the present invention relate generally to a signal transmission circuit and method thereof.
2. Description of the Related Art
A micro strip line pattern or a strip line pattern may be provided to control transmission characteristics of a signal transmission circuit. In conventional micro strip line structures, a reference transmission plane having a ground voltage or a power voltage may be located under a signal transmission line. In conventional strip line structures, a plurality of reference transmission planes may be respectively arranged on and under a plurality of signal transmission lines. The signal transmission lines and the reference transmission planes of the strip line structures may be electrically separated from each other by a plurality of insulating layers. The transmission characteristics of the signal transmission circuits may be adjusted via the pattern of the signal transmission lines or the reference transmission planes.
FIG. 1 is a perspective view of a conventional signal transmission circuit. The signal transmission circuit of FIG. 1 may include a plurality of first through fifth signal transmission lines SL1, SL2, SL3, SL4 and SL5 and a plurality of reference transmission planes RP1 and RP2, and a plurality of insulating layers D1, D2 and D3. The plurality of first through fifth signal transmission lines SL1, SL2, SL3, SL4 and SL5 may be formed from a plurality of metal layers, the plurality of reference transmission planes RP1 and RP2 may be formed from a plurality of metal layers.
FIG. 2 illustrates a portion of the first and second signal transmission lines SL1 and SL2 and the reference transmission plane RP1 of FIG. 1. Interference (e.g., cross-talk) between neighboring signal transmission lines will now be explained with reference to FIG. 2.
Referring to FIG. 2, the first signal transmission line SL1 may transmit a first signal current Is1 and the second signal transmission line SL2 may transmit a second signal current Is2. The reference transmission plane RP1 may transmit a return current Ir1 corresponding to the first signal current Is1 and a return current Ir2 corresponding to the second signal current Ir2.
Referring to FIG. 2, in the reference transmission plane RP1, electromagnetic wave noise Nw accompanying the return current Ir1 may affect the second signal current Is2 and electromagnetic wave noise Nw accompanying the return current Ir2 may affect the first signal current Is1, thereby resulting in cross-talk between the first and second signal transmission lines SL1 and SL2. Further, if a higher-frequency signal is transmitted through the signal transmission lines, the cross-talk may increase, which may further degrade system performance.